black color milk coming from breast its normal or not

Hello and welcome to EmpowHer,
Due to the abnormal color of the discharge, you should see a doctor as soon as possible.
Breast discharge can be white, yellow or green and still be normal. But black can indicate dark blood which is always a red flag.
Causes of abnormal breast discharge can include:

--Fibrocystic breast changes
--Galactorrhea: breast secretes milk even when not breast feeding
--infection
--Mammary duct ectasia: inflammation and blockage of breast ducts
--Intraductal papilloma: noncancerous growths in breast ducts

Below I have posted a link to a HER article that talks more about breast discharge and possible causes.
https://www.empowher.com/breast-discharge/content/breast-discharge-what-does-it-mean
I hope that helps.
Faith